A gas turbine that is used in a thermal power station, etc. comprises an air intake portion, a compressor, a combustor and a turbine portion. Air is taken in from the air intake portion and is supplied into the compressor to be compressed to become compressed air. The compressed air is sent to the combustor, where the compressed air and fuel are mixed together to be continuously used for combustion. High temperature and high pressure combustion gas is generated by the combustion and this combustion gas is supplied into the turbine portion.
By passing of the combustion gas, moving blades of the turbine portion are driven and a rotor integrated with the moving blades is rotated. Thereby, a generator connected to the rotor is driven and generates electric power.
If foreign matters, such as dust, are included in the air supplied into the compressor, the foreign matters stick to the blades of the compressor to thereby reduce the compression efficiency. Thus, in order to remove the foreign matters, filtering of the air is carried out by a filter in the air intake portion. Generally, the filter comprises a frame, made of metal material or the like, and a filter cloth fitted to the frame.
If the filter is used for a long time, clogging of the filter cloth occurs to thereby invite an increase of pressure loss. Thus, a periodical replacement of the filter is needed. Usually, the filter is replaced in the frequency of once per 3 to 12 months and the filter after used is disposed as industrial waste.
Also, as the gas turbine consumes a large amount of air, a multiplicity of filters are needed. For example, in a usual gas turbine, 1000 or more filters, each having an opening area of 0.35 m2 or so, are used, or in a larger gas turbine, some 5000 filters are used.
Thus, on each occasion of the replacement of the filter, an extremely large amount of industrial waste arises and this causes problems from the viewpoint of the environment preservation and resource saving. Also, replacement of the multiplicity of filters invites a large increase of running cost of the gas turbine power generation plant.
In view of the abovementioned problems, trials are recently being carried out for re-using the used filters by washing them. While various methods for washing the used filters are proposed and being studied, one of them makes use of an ultrasonic washer.
In performing the wash by the ultrasonic washer, the used filters are dipped in wash liquid. By the ultrasonic wave, cavitations are generated in the wash liquid. By the impact force caused when the cavitations disappear, the dust sticking to the filter cloth is removed.
By this wash, the filter returns to the state of pressure loss as if it is almost a new filter. The washed filter is mounted on the gas turbine to be re-used for a predetermined period and is then washed again.
As mentioned above, the use and wash of the filter are repeated alternately for several times. This is what is called a recycle use of products and thereby both of suppression of industrial waste and cost reduction can be realized.
In the mentioned wash process, however, there are often caused a damage of the elements, such as filter cloths, and a breakage of connection portions of the elements by fluid pressure of the wash liquid or the like. Hence, re-use of all of the filters sent for the wash is difficult and a process loss must be estimated to some extent.
Also, if not a breakage, deterioration of the elements occurs due to the repeated washes and this invites a gradual lowering of the filter performance.
Thus, there is a limitation in the number of times of the wash, that is, the number of times of the re-use, and it is preferable to monitor the maintenance or past history, such as the number of times of wash, for each of the filters.
In the usual maintenance monitoring mode of the filters of this kind, a person or company (for example, a power company) who owns the gas turbine for his own business buys and owns the filters therefor and performs the operation and maintenance by himself based on his own operation standard or the like. That is, the owner of the gas turbine sends the filters to be washed for re-use after the filters have been once used for operation of his own gas turbine.
But, as mentioned above, there is the loss in the wash process and not all of the filters can be re-used. Hence, the filters corresponding to the lost filters must be supplemented.
Also, from the viewpoint of a stable operation of the gas turbine, the owner of the gas turbine must continuously have the supplemental filters in a sufficient quantity, which is a large burden on the owner. Further, if seen in the electric power industry only, there are many gas turbine owners, and if many supplemental filters are to be owned by each of the owners, it will be quite inefficient as the whole industry. Moreover, such inconvenience may lead to an obstruction in promoting the re-use of filters by wash.
Therefore, as one of filter maintenance monitoring modes, such one will be necessary to be considered that a gas turbine owner and a filter owner are separated from each other, wherein the former will be the user of the filter loaned from the latter, such as on a lease arrangement, and the latter will be the monitor of the filter maintenance, or such mode is considered that there exists what is called a leasing company inbetween in the abovementioned mode.